The original flag of the City of Buda 1703-1873 was:
red-white-green horizontal, (like the Hungarian flag now)
The original flag of the City of Pest 1703-1873 was:
blue-yellow-red horizontal
You can see the proposals at <www.budapest.hu>,
which are the union of the two city flags.István Molnár, 12 October 2000

The Red-white-green stripes are not the colours of the
national flag, but these are the colours of the flag of City of Buda 1703-1873. István Molnár, 15 October 2000

The flag of Budapest before 1989 was: White with the Coat of
Arms, but without the Holy Crown and the two animals, but with
the great red star on the "blue river"István Molnár, 15 June 2000

At <www.budapest.hu>
page:
Between 1948/49-1966/68 no coat of arms and no flag.
Between 1968/73-1989 was a coat of arms and it was used on white field as
flag.István Molnár, 14 October 2000

After the WW I., after the Rumanian occupation in Budapest,
the city council changes the blue colour to green. Too much time
they had to see the Rumanian colours in our capital- they said.
This flag had been used from about 1920 to about 1950. István Molnár, 15 June 2000

The change of the colours (blue/green) was in 1930! The
red-yellow-blue flag was used 1873-1930.
The red-yellow-green flag was used 1930-1946/1950. The present
flag is the red-yellow-blue from 1989.István Molnár, 19 October 2000

Flag used between 15 and 31 August 2011
image by Zoltan Horvath, 16 June 2011

Budapest Assembly is going to make a decision on the new flag of Budapest on
next Wednesday - reported an on-line news-agency. The new flag will be white
with green and red wolf-teeth around the white field, which is charged with CoA
of Budapest in the center of the white flag. Ratio is 3:4.
Article (in Hungarian):
http://index.hu/belfold/budapest/2011/06/16/szerdan_dontenek_budapest_uj_zaszlajarol/
If the Assembly adopts the proposal of Mayor, new flag would be hoisted at the
first time on 15 August 2011.Zoltan Horvath, 16 June 2011

Is this the flag of county of Buda, or of the city of Buda?
eljko Heimer, 10 May 1997

According to by Sandor Kiss (HMKS) , this is
Budapest 1974-1989 flag. Dov Gutterman, 6 October 1999

I spotted this flag in Budapest (in Buda, actually) in 1997.Antonio Martins , 7 October 1999

I am afraid that this flag never was flag of Budapest. I see
this flag on the City Hall of Budava'r (Budapest I. district)!Istvan Molnar, 12 October 2000

It also flies on the two entrance gates of the upper city of
Buda, and I guess it shows the limit of the Budavar district
(does Budavar exactly match the upper city of Buda?).?). The toll
gates are also painted in yellow and red. So the flag might have
been the flag of Buda before the merging of Buda and Pest in
Budapest.Ivan Sache, 12 October 2000

No, the territory of the "Community of Budapest I.
district Budavár" is greater (included the old suburbs
around the Castle Hill: Tabán, Krisztinaváros, Viziváros
(Wasserstadt), Naphegy (Sun Hill). In the book "Széll S.:
Városaink neve, címere es lobogója, Bp 1941" I found this
flag as the flag of Buda, but in the official homepage of
Budapest there is the red-white-green flag 1703-1873.Istvan Molnar, 14 October 2000